Arrangement for excitation of continuous-current generators.



L. SCHD'N.

ARRANGEMENT FOR EXCiTATION OF CONTINUOUS CURRENT GENERATORS.

' APPLICATION FILED JAN. 7. 1914.

. z a a3 I 4 r B /B Invenl'mj Ludwig Scla'o'n Aft v.8.

- in the main field winding D. The rotor UNITED STATES PATENT OFFICE.

LUDWIG SCI-13611, 0F ESSEN-ON-THE-RUHR, GERMANY, ASSIGNOR T0 FRIED. KRUPP AKTIENGESELLSCHAFT, 0F ESSEN-ON-THE-RUHR, GERMANY.

ARRANGEMENT FOR EXCITATION OF CONTINUOUS-CURRENT GENERATORS.

Specification of Letters Patent.

Patented July 11, 1916.

Application filed January 7, 1914. Serial No. 810,852. 7

To all whom it may concern:

Be it known that I, LUDWIG SoHoN, re-

siding at Essen-on-the-Ruhr, Germany, a subject of the Emperor of Germany, have invented a certain new and useful Improvement in Arrangements for Excitation of Continuous-Current Generators, of which the following is a specification. o The present invention relates to arrangements for excitation of continuous current generators particularly intended for controlling dynamos with Leonard-driving, the exciting current of which is to be furnished by an external source of constant voltage connected in opposition to the armature of said generator. The subject matter of the present invention is an arrangement of this kind, by which the maximum voltage of the armature of the generator, which is to be excited, is made independent of the height of the available external voltage.

In the accompanying drawing one em- 'bodiment of this invention is diagrammatically illustrated.

A denotes a continuous current generator, the excitation of which is to be changed by the regulation of the current strength C of a continuous current motor is, by means of the conductor B, connected with the armature brushes a and a of the generator A, the field winding C of said motor being separately excited in well known manner. The negative armature brush a of the generator A is connected with one end k of a regulating resistance H, by means of a conductor F and the positive brush a of the generator A is connected with the other end k of the resistance by means of a conductor F. The negative pole of a constant external voltage source G is moreover connected to the point 7L and the positive pole of the same source G connected with a point 71. situated between the ends k and k of the regulating resistance H. The

main field winding D is on the one hand connected with an auxiliary brush a of the generator armature, and on the other" hand with the sliding contact E of the resistance H. The auxiliary brush a resting on a slip-ring a connected to one point of the winding of the generator armature serves the purpose to divide the armature voltage in the manner of the well known Sengel arrangement operates like the known arrangements for exciting a continuous current generator by means of a constant external voltage source connected in opposition to the generator armature and producing a constant voltage at the brushes a and a. The only difference is, that the value of the voltage opposed to the portion of the external voltage which is determined by the position of the sliding contact E, is only half of the armature voltage. Therefore, the strength of the-exciting current running through the circuit G, E, D, a a F G depends on the diilerence of the external voltage and the half armature voltage.

When the contact E is situated in point h half of the value of the armature voltage is equal to the external voltage less the voltage drop in the winding D, or, in other words, the voltage between the brushes a and a is smaller than the external voltage. Should, however, the contact E be moved in the direction of the arrow as past the point h, the generator will then behave as a self-exciting dynamo, and it will self excite to a greater degree, the more the contact E is moved toward the end it of the resistance H. The exciting current now mainly runs through the circuit a F, 71, H, E, D, u When, finally, the contact E reaches the point 72?, the generator A is wholly self excited. Evidently, with the arrangement described, the armature voltage sistance connected w nected on the one 'hand with the third one of said brushes and on the other hand with said sliding contact.

2. An arrangement for exciting continuous current generators having two main brushes and an auxiliary brush for dividing the voltage of the main brushes, an external source of constant volt'fia, a regulating rebrushes, a portion of said resistance serving. to connect the armature 1n opposition to said external voltage source, a sliding contact for "the two mainsaid resistance and a main field winding connectedon the one hand with said auxiliary brush and on the sliding contact.

The foregoing specification signed at Bar- HELEN NUFER,

"Amnn'r Nam. j

other hand with said 15 

